1. [n]  a jazz ostinato; usually provides a background for a solo improvisation
2. [n]  a Berber living in northern Morocco
3. [v]  look through a book or other written material; "He thumbed through the report"; "She leafed through the volume"

RIFF is a 4 letter word that starts with R.

microsoft's equivalent to the amiga's iff files format. RIFF is used for wav and avi files.